Chilling systems for food such as frozen custard or ice cream making machines are discussed in U.S. Pat. Nos. 6,119,472, 6,370,892, 6,101,834, and 5,755,106. Ice cream making machines can generally include a cooling chamber surrounded by an evaporator. The ice cream or frozen custard is agitated and frozen in a batch mixing chamber or barrel so that the quantity of ice cream is produced as the result of one operation. A “gate” or “knife” valve of such conventional ice cream making machines dispenses the ice cream from the barrel to a container. Such ice cream making machines typically provide ice cream when such valve is slid from a “down” or closed position to an “up” or opened position.
Conventional ice cream machines have included a motor driven auger for mixing the liquid ice cream and frozen ice cream within the chamber or barrel. The auger is generally provided in a cylindrical cooling chamber. The auger includes paddles, blades or impellers that mix the ice cream and wipe the internal surfaces of the barrel free of ice cream product.
The motor driven auger is also utilized to transfer the ice cream from the input of the chamber or barrel to the output of the chamber or barrel (associated with the gate). Generally, smaller ice cream machines and batch freezing ice cream machines have utilized a motor with relatively limited capabilities. Smaller ice cream machines and batch freezing ice cream machines typically have utilized a motor that allows only two speed agitation. Such machines have typically not utilized reverse agitation.
The limited motor capabilities have not allowed the operator to mix ice cream at a variety of speeds. The mixing speed can affect the amount of air mixed into and/or fluffiness of the finished ice cream product (generally called overrun). It is desirable to allow the user to customize the final ice cream product for fluffiness.
It has been desirable to manufacture food stuffs including solid or semi-solid materials or inclusions. For example, mixing nuts, granola, chocolate and other chips, foodstuffs, candy bars, cookies, fruits, or other morsels (referred to generically in this application as inclusions) into ice cream has been utilized to develop many flavors that are highly desired by customers. Typically, such solid or semi-solid inclusions are placed in the cooling chamber or barrel of the ice cream machine along with the liquid ice cream. The motor driven auger used to mix or agitate the liquid ice cream and transport the frozen ice cream to the front of the chamber or barrel also mixes the solid or semi-solid inclusions. This mixing can cause the solid or semi-solid inclusions to be ground or reduced in size.
Other conventional techniques for mixing inclusions with ice cream place the solid or semi-solid inclusions into the chamber or barrel after the ice cream has been frozen or partially frozen. Typically, inclusions are added during the last few minutes of the freezing operation when the consistency of the mix is thick. The thick consistency makes it difficult to transport inclusions into the barrel or chamber, much less evenly distribute the inclusions within the ice cream.
Further, using a forward mixing motion does not allow complete mixing of the solid or semi-solid inclusions with the frozen ice cream because the inclusions are pushed to the front of the barrel or chamber. When inclusions are pushed to the front of the chamber, the inclusions are not fully mixed with the ice cream product at the rear of the chamber. The front of the barrel or chamber is where the ice cream exits at the gate.
When the ice cream has reached a particular consistency suitable for serving, the gate can be opened and ice cream can be removed from the chamber. Generally, it is desirable to determine the temperature within the chamber to determine the consistency of the ice cream. In other words, a method is required for determining the appropriate time to end the freezing operation and to initiate the discharge procedure for the ice cream product.
Heretofore, smaller ice cream machines and batch freezing ice cream machines have determined such temperature through historical time, and the measurement of the amperage provided to the motor that drives the auger. Certain conventional soft serve machines have used indirect temperature readings. According to the indirect technique, product temperature is estimated not by measuring actual temperature, but by measuring the temperature of surrounding components and estimating the product temperature. Such conventional systems do not provide a highly accurate apparatus for and method of obtaining actual temperature of the product within the cooling chamber.
Therefore, there is a need for a machine for making ice cream that can regulate the speed of mixing in an ice cream machine or foodstuff freezing machines. Further, there is a need for a machine and method of making ice cream with solid or semi-solid inclusions without grinding the inclusions. Further, there is a need for a motor system that more selectively controls the mixing of ice cream. Further still, there is a need for a machine for making ice cream having a reversing motor. Yet even further, there is a need for a system and method of determining the temperature within the cooling chamber with more accuracy. Yet further, there is a need for an ice cream machine having one or more of these or other advantageous features.